JPH0712919Y2 - Oxygen sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to an oxygen sensor used for detecting the oxygen concentration in exhaust gas, for example, in an internal combustion engine, especially in an air-fuel ratio control device thereof.

<Prior Art> Conventional oxygen sensors of this type are disclosed in Japanese Utility Model Publication Nos. 59-12602 and 59-81882. In such an oxygen sensor, conventionally, in order to shut out noise around the lead wire for sensor output and obtain an accurate sensor output, a so-called noise-proof seal conductor is wound to form a shield wire. There is something.
The technology of this shielded wire is, for example,
No. 14 is disclosed.

An example structure of such an oxygen sensor is shown in the structural diagram of FIG. 3, the circuit diagram of FIG. 4 and the sectional view of the waterproof structure portion of FIG.

In these figures, the sensor unit 1 is composed of a sensor element 2, a heater 3 for heating the sensor element 2, and a resistor 4.
A lead wire 5 for sensor output, a lead wire 6 for sensor power supply and a heater power supply, and a lead wire 7 for grounding are connected to the sensor portion 1.

As described above, the noise-proof seal conductor 8 is wound around the sensor output lead wire 5, and is configured as a shield wire. The seal conductor 8 of this shield wire is separated from the periphery of the lead wire 5, and the separated seal conductor 8
8a is connected to the lead wire 10 for the seal conductor by the caulking metal fitting 9.

The lead wires 5 and 10 have a structure in which the central conductive wires 5a and 10a are covered with insulating tubes 5b and 10b, respectively. Although not shown, the lead wires 6 and 7 have the same structure.

The lead wires 5, 6, 7, 10 are connected to the connector coupler 14. Further, the periphery of the seal conductor 8 located around the lead wire 5 is covered with the covering material 11.

Here, a multi-core wire is generally used as the seal conductor 8 and the lead wire 10 for the seal conductor 8. However, since this multi-core wire has a structure in which a fine gap exists between wire rods,
It is necessary to employ a waterproof structure on the exposed portions of the seal conductor 8 and the lead wire 10 for the seal conductor 8 in the separated portion to shield the seal conductor 8 and the lead wire 10 from water.

Therefore, conventionally, the exposed portion is covered with the two heat-shrinkable tubes 12 and 13, and the exposed portion is fastened with the heat-shrinkable tubes 12 and 13.

<Problems to be Solved by the Invention> However, the conventional waterproof structure as described above has the following problems.

That is, by simply tightening the outside of the exposed portion requiring waterproofing as described above with the heat shrinkable tubes 12 and 13,
Adhesion between the exposed portion and the heat-shrinkable tubes 12 and 13 cannot be said to be good, and a small gap remains, and water enters through this gap.

The invading water reaches the inside of the connector coupler 14 through a fine gap between the wire rods of the seal conductor 8 and the lead wire 10 for the seal conductor 8 as described above, and the other conductors in the connector coupler 14 are separated from each other. It lowers the insulation resistance of the sensor and causes sensor output failure and lead wire corrosion.

Further, there is a problem that the water that has penetrated through the gap reaches the connection portion between the seal conductor 8a and the seal conductor lead wire 10 by the caulking metal fitting 9, which is likely to cause poor contact, and causes poor contact.

Therefore, in view of the above conventional problems, the present invention provides a seal conductor formed of a multi-core wire, a fine gap between the wire materials of the lead wire, and a connecting portion between the seal conductor by the caulking tool and the seal conductor lead wire. By adopting a waterproof structure that does not intrude, it is possible to prevent a decrease in insulation resistance from other lead wires in the connector coupler, a sensor output failure, corrosion of the lead wire itself, and contact failure. To aim.

<Means for Solving the Problems> Therefore, in the oxygen sensor of the present invention, a seal conductor is wound around at least one lead wire among a plurality of lead wires connected to the sensor section to form a shield wire, In an oxygen sensor in which the seal conductor of the shielded wire is separated from the periphery of the lead wire, and the separated seal conductor is connected to the seal conductor lead wire by a caulking tool, the seal conductor and the seal conductor lead wire in the separated part of the seal conductor An adhesive filler was wound around a portion of the exposed portion including the connecting portion between the seal conductor by the caulking tool and the seal conductor lead wire.

<Operation> In such a configuration, the adhesive filler is plastic and viscous, so that it is filled around the seal conductor and the lead wire for the seal conductor, which are composed of multi-core wires. Alternatively, it is filled into the fine gaps between the wire rods. Further, the connecting portion between the seal conductor and the lead wire for the seal conductor by the caulking tool is filled.

Therefore, the waterproof structure of the portion including the connecting portion between the seal conductor and the seal conductor lead wire by the caulking tool in the exposed portion of the seal conductor and the seal conductor lead wire in the separated portion of the seal conductor becomes perfect, and the seal conductor and the seal conductor The lead wire for the seal conductor and the connecting portion between them can be reliably shielded from water.

Therefore, when the seal conductor in the separated portion of the seal conductor and the exposed portion of the seal conductor lead wire are used under the condition that water is applied to the portion including the connection portion between the seal conductor and the seal conductor lead wire by the caulking tool. However, water does not enter the gap between the seal conductor and the wire of the lead wire for the seal conductor, and water does not enter the connector coupler. Water can be prevented from entering the connection.

As a result, it is possible to prevent a decrease in insulation resistance from other lead wires, a defect in sensor output, and a corrosion of the lead wire itself, and a contact failure.

<Embodiment> An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, the same elements as those in FIG. 5 are designated by the same reference numerals to simplify the description.

In the figure, a noise-proof seal conductor 8 is wound around the sensor output lead wire 5 and configured as a shield wire. The seal conductor 8 of this shield wire is separated from the lead wire 5 and its separation. Sealed conductor
The structure of 8a is connected to the lead wire 10 for the seal conductor 8 by the caulking metal fitting 9, which is the same as the conventional one.

Then, a portion of the exposed portion of the seal conductor 8 and the lead wire 10 for the seal conductor 8 in the separated portion that includes the connecting portion between the seal conductor 8a and the seal conductor lead wire 10 by the caulking tool 9 is adhered with butyl rubber or the like. A permeable filler 15 is wrapped around. Also, vinyl tape around this filling material 15
16 is wrapped around.

Since the adhesive filler 15 such as butyl rubber has plasticity and viscosity, it is filled into the fine gaps between the seal conductor 8 formed of the multi-core wire and the lead wire 10 as well.
Further, the caulking tool 9 is filled in the connection portion between the seal conductor 8a and the seal conductor lead wire 10.

Therefore, the waterproof structure of the portion including the connecting portion between the seal conductor 8a and the seal conductor lead wire 10 by the caulking tool 9 on the exposed portion of the seal conductor 8 and the lead wire 10 in the separated portion becomes perfect, and the seal conductor 8 It is possible to reliably shut off the water, the lead wire 10 and the connecting portion between them.

Therefore, the seal conductor 8 and the lead wire 10 at the separated portion
Even when the seal conductor 8a and the lead wire 10 for the seal conductor are exposed to water at the exposed portion of the seal conductor 8a and the seal conductor lead wire 10, the seal conductor 8 and the lead wire 10 are Water does not enter the gap between the wire rods, water does not enter the connector coupler 14 shown in FIG. 3, and water enters the connecting portion between the seal conductor 8a and the seal conductor lead wire 10. Never.

As a result, it is possible to prevent a decrease in insulation resistance from other lead wires in the connector coupler 14, a sensor output failure, and corrosion of the lead wire itself, as well as contact failure.

In the above-described embodiment, the shield wire is formed by winding the seal conductor around one lead wire among the plurality of lead wires connected to the sensor portion. However, a plurality of shield wires are provided. The same waterproof structure can be used for the same thing, and the same action and effect are achieved.

Incidentally, as a conventional technique of applying a waterproof filler in an oxygen sensor, there is one described in JP-A-57-120851. However, this technique does not have a noise-proof shielded wire and is not waterproof. The filled portion of the filling material is also a portion where the lead wire enters the sensor portion, and is different from the configuration of FIG.

Here, in the conventional oxygen sensor, since all the lead wires were connected to a single connector coupler, water entered the connector coupler through the gap between the seal conductor and the wire rods of the lead wire for the seal conductor. If it did, the influence of water had spread to other lead wires in the connector coupler.

Therefore, as shown in FIG. 2, the lead wire 10 on the insufficient waterproof side where water may enter is connected to the separately-provided connector coupler 14A.

As a result, even if water enters the connector coupler 14A from the lead wire 10 on the insufficient waterproof side, the other lead wires 5,
No influence is spread to the 6th and 7th side, and the conventional problems can be solved.

Although FIG. 2 shows an example in which one connector coupler 14A is provided separately, it is provided separately as two, three, ... It is sufficient to connect the lead wires on the opposite side to each other and connect all other lead wires to the original connector coupler all together.

Incidentally, as a technique in which a plurality of connector couplers are separately provided in the oxygen sensor, there is one disclosed in Japanese Patent Laid-Open No. 57-64750, but this one does not have a shield wire for noise prevention and has a high voltage current. 2 is provided separately, and a separate connector coupler is provided for this lead wire, which is different from the configuration of FIG.

<Effects of the Invention> As described above, according to the present invention, a seal conductor is wound around a lead wire to form a shield wire, the seal conductor of the shield wire is separated from the lead wire, and the separated seal conductor is removed. In an oxygen sensor that is connected to a seal conductor lead wire by a caulking tool, the seal conductor at the separated portion of the seal conductor and the seal conductor and the seal conductor lead wire at the exposed portion of the seal conductor lead wire are connected by the caulking tool. Since the adhesive filler is wound around the part including the part, the waterproof structure of the seal conductor consisting of multi-core wire and the wire of the lead wire and the connecting part of the seal conductor and the lead wire for the seal conductor is perfect. It is possible to reduce the insulation resistance from other lead wires in the connector coupler, malfunction of the sensor output, corrosion of the lead wire itself, and contact. This is a great practical effect that can prevent the occurrence of touch defects.

[Brief description of drawings]

FIG. 1 is a view showing an embodiment of an oxygen sensor according to the present invention, a sectional view of a waterproof structure, FIG. 2 is a front view showing another waterproof countermeasure structure, and FIG. 3 is a front view of a conventional oxygen sensor. Figure, 4th
FIG. 5 is a circuit diagram of the above oxygen sensor, and FIG. 5 is a sectional view of a conventional waterproof structure. 1 ... Sensor part, 5, 6, 7 ... Lead wire 8 ... Seal conductor, 10 ... Lead wire for seal conductor 15 ... Adhesive filler

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Minoru Nasu Minoru Nasu 14-18 Takatsuji-cho, Mizuho-ku, Nagoya-shi, Aichi Nihon Special Ceramics Co., Ltd. (56) Bibliography 55-146614

Claims (1)

[Scope of utility model registration request] 1. A shield conductor is formed by winding a seal conductor around at least one lead wire of a plurality of lead wires connected to a sensor section, and separating the seal conductor of the shield wire from the circumference of the lead wire. In the oxygen sensor in which the sealed seal conductor is connected to the seal conductor lead wire by a caulking tool, the seal conductor in the separated portion of the seal conductor and the exposed portion of the seal conductor lead wire are sealed by the caulking tool and the seal conductor An oxygen sensor characterized in that an adhesive filler is wound around a portion including a connecting portion with a lead wire.